1. Field
Embodiments relate to memory modules on which semiconductor memory modules are mounted. More particularly, embodiments relate to a selectively recessed reference plane structure in a module tab area of a memory module and a method for forming a selectively recessed reference plane.
2. Description of the Related Art
A dynamic random access memory (DRAM) or a magnetic random access memory (MRAM) may be used as a main memory of a memory system. For example, in order to increase capacity of a DRAM, a plurality of semiconductor memory chips may be mounted on a single substrate to constitute a memory module.
A memory module may be classified into a single in-line memory module (SIMM) and a dual in-line memory module (DIMM). A SIMM is an older memory module in which pins are formed on only one surface of a printed circuit board (PCB), while a DIMM is a module in which pins are formed on both surfaces of a PCB.
Memory chips may be mounted on one surface or both surfaces of a PCB in both a SIMM and a DIMM. However, due to structural characteristics, memory chips are generally mounted on one surface of a PCB in a SIMM and on both surfaces of a PCB in a DIMM.